PHC piles have become one of the widely used foundation treatment methods in soft soil foundations, but there is little research on the reliability based on the load-displacement curve of uplift piles. The probability regression parameter method can be used to fit the loading section of the PHC uplift load-displacement curve using two parameter exponential functions, hyperbolic functions, and power functions, with goodness of fit greater than 0.98; The unloading section can be fitted using linear and power functions, with goodness of fit greater than 0.85 and 0.94, respectively. The reliability analysis of uplift PHC bearing capacity based on power function fitting function shows: (1) The safety factor and reliability index increase with the increase of allowable displacement; (2) When the safety factor is constant, the variability of parameter aLP in the power function fitting function has the greatest impact, followed by the variability of load, the impact of the variability of fitting parameter bLP on the reliability index can be ignored.